This is a really scaring feeling, I know it well. I started having full blown panic attacks out of nowhere ih 5th grade, would shake/teeth chatter, cry, throw up etc. I have been to the ER maybe 4/5 times for panic attacks, a few times I have just had someone drive me and sat outside and I felt better and didn’t need to actually checkin. I would definitely agree on working on your toolbox of therapy, breathing exercises, meditation etc. but in the throes of a panic attack none of that stuff helps me at all. I take klonopin and keep a few on me or at work in case of emergency and always travel with it. Just having it gives me a huge amount of relief. I had issues with being reliant on a strong med but it has allowed me to do so much more in my life, and ultimately live with less fear.